AFRS means "Active Front & Rear Steering", i.e., four wheel independent steering. And of course, each of the four motors has its own independently-set speed.
I've added a small amplifier and a tiny speaker that can play MP3 files so the robot can make some noise, and an ESP32-Now based remote controller (an Unexpected Maker Explorer shield) so the robot now has a kill switch.
This second test includes some new code (courtesy of Jon Hylands, thank you!) that compensates for the difference in angles between the inner and outer wheels when rotating clockwise or counter-clockwise. This is partially compensated because all four wheels are going the same speed, where the inner wheels are moving through a smaller arc than the outer wheels and therefore should be going slower. You can see the inner wheels slipping on the deck as they're going too fast. Fixing that is next.
The test script has the robot roughly traversing an infinity sign pattern, set entirely by the manually-set speed of the motors and the timings in the script, so it's imperfect. A better solution would be to use the IMU (mounted at the top of that wooden mast) to determine the rotation of the robot. That's also next.
Lots of nexts…